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Abstract:

One embodiment of an actuator system for a power dental cleaning
appliance to produce a tapping motion of bristle tufts in a dental
cleaning appliance includes a plurality of piston elements (16) mounted
in a brushhead for movement away from and then toward the brushhead (12).
Bristle tufts (20) are positioned on the piston elements and move
sequentially against and away from the teeth to produce a cleaning
action. A low frequency fluid pressure action (40) in the range of 1-6 Hz
maintains conformity of the bristle tufts in a low frequency sequence
against the teeth, while a higher frequency fluid pressure action (42) in
the range of 100-300 Hz moves the bristle tufts at that frequency to
produce a tapping bristle action on the teeth to produce cleaning. In
another embodiment, an actuation system includes an elongated actuator
member (52) made of elastic material which expands and contracts about
its longitudinal axis at a selected frequency by fluid pressure. A
plurality of actuator sections (56) are fixedly mounted on the actuator
element. The actuator sections are configured such that as the actuator
member expands, an upper bridge portion (63) of the actuator section
moves upwardly. The bristle tufts (74) mounted thereon produce a cleaning
action on the teeth.

Claims:

1. A dental cleaning appliance, comprising: an appliance body (14) having
a brushhead portion (12) with a plurality of movable piston members (16)
mounted therein for in-and-out movement thereof toward and away from the
teeth when a distal end of the brushhead portion is positioned in the
mouth; bristle tufts (20) mounted on the piston members, for cleaning
contact with the teeth; a low frequency actuator (40) for moving the
piston members at a low frequency to generally sequentially conform tips
of the bristle tufts to the teeth; and a higher frequency actuator (42)
for moving the piston members at a higher frequency relative to the teeth
to produce cleaning of the teeth by periodic contact between the bristle
tufts and the teeth.

2. The dental-cleaning appliance of claim 1, wherein the bristle cleaning
action is a tapping action against the teeth.

3. The dental cleaning appliance of claim 1, wherein the higher frequency
is at least 30 times greater than the low frequency.

4. The dental cleaning appliance of claim 1, wherein the low frequency is
in the range of 1-6 Hz, and the higher frequency is in the range of
100-300 Hz.

6. The dental cleaning appliance of claim 5, wherein the low frequency
actuator is a spring member and wherein the higher frequency actuator is
a linear actuator/piston assembly.

7. The dental cleaning appliance of claim 6, wherein the higher frequency
actuator is mounted on the spring member.

8. A dental cleaning appliance, comprising: an appliance body (50),
including a driving system (53) having an elastic elongated actuator
member (52) which expands and contracts about its longitudinal axis at a
selected frequency; a plurality of actuator sections (56) fixedly mounted
on the actuator member, each actuator section being configured so that as
the actuator member expands, an upper portion (63) of the actuator
section moves upwardly; and bristle tufts (74) mounted on the upper
portion of each actuator section such that as the actuator member
expands, the upper portion of the actuator section and the bristle tufts
mounted thereon move alternately outwardly and then back, toward and away
from the teeth when the appliance is positioned in the mouth.

9. The dental cleaning appliance of claim 8, wherein the bristle tufts
move a distance at least seven times the amount of the expansion of the
actuator member.

10. The dental cleaning appliance of claim 8, wherein the bristle tufts
move a distance approximately 40 times the expansion of the actuator
member.

11. The dental cleaning appliance of claim 8, wherein each actuator
section includes a base portion (58) and an upper narrow bridge portion
(63), with an open area between the bridge portion and the base portion,
wherein the base portion includes a slot (76) which extends from a first
opening (70) therein, through which opening the actuator member extends,
to an edge of the base portion of the actuator section and further
includes hinge portions (86, 88) on the base portion on opposing sides of
the center line of the actuator section above the first opening, and
wherein the bridge section includes three hinge portions (66, 68, 70),
one at each end thereof where the bridge portion joins the base portion,
and one approximately at a center point of the bridge portion, such that
as the actuator member expands in diameter, two parts (84, 85) of the
base portion move away from each other about the base portion hinge
portions, forcing the bridge portion upwardly along with the bristle
tufts mounted thereon.

12. The dental cleaning appliance of claim 11, wherein the actuator
sections are oval in outline.

13. The dental cleaning appliance of claim 8, wherein the frequency of
movement of the actuator member and the bristle tufts is within the range
of 100-300 Hz.

14. The dental cleaning appliance of claim 8, wherein the actuator
sections are made from a hard plastic.

15. The dental cleaning appliance of claim 8, wherein the base portion
includes a second opening (78) above the first opening, symmetrical about
a center line of the actuator section, the base portion of the actuator
section further including a third opening (82) between the second opening
and an upper surface of the base portion, wherein the first and second
hinge portions defined partially by the second opening and are on
opposite sides of said third opening.

Description:

[0001] This invention relates generally to power dental-cleaning
appliances which utilize a bristle action directly toward and away from
the teeth, i.e. approximately perpendicular to the teeth, and more
specifically concerns such an appliance which operates within selected
ranges of frequency and bristle stroke.

[0002] It is known that a tapping/light hammering action of bristles
against teeth surfaces can produce effective cleaning of teeth, including
interdental regions. But the effectiveness of such appliances depends
upon a relatively short bristle stroke, as well as a certain frequency
range, to produce effective results. Fluid (gas or liquid) pressure
actuators have certain design advantages in such an appliance relative to
other types of actuators, but the effect of cavitation in liquid caused
by the actuator prevents effective movement of the bristle tuft field at
frequencies above 80 Hz. Effective cleaning typically requires a
frequency in the range of 100-300 Hz.

[0003] Accordingly, it is desirable to have a fluid pressure actuator
which can produce a bristle tapping action with an effective stroke
length and a frequency within a desired range, e.g. 100-300 Hz.

[0004] One embodiment of a dental cleaning appliance comprises: an
appliance body having a brushhead portion with a plurality of movable
piston members mounted therein for in-and-out movement thereof toward and
away from the teeth when a distal end of the brushhead portion is
positioned in the mouth; bristle tufts mounted on the piston members, for
cleaning contact with the teeth; a low frequency actuator for moving the
piston members at a low frequency to generally sequentially conform tips
of the bristle tufts to the teeth; and a higher frequency actuator for
moving the piston members at a higher frequency relative to the teeth to
produce cleaning of the teeth by periodic contact between the bristle
tufts and the teeth.

[0005] Another embodiment comprises: an appliance body, including a
driving system having an elastic elongated actuator member which expands
and contracts about its longitudinal axis at a selected frequency; a
plurality of actuator sections fixedly mounted on the actuator member,
each actuator section being configured so that as the actuator member
expands, an upper portion of the actuator section moves upwardly; and
bristle tufts mounted on the upper portion of each actuator section such
that as the actuator member expands, the upper portion of the actuator
section and the bristle tufts mounted thereon move alternately outwardly
and then back, toward and away from the teeth when the appliance is
positioned in the mouth.

[0006] FIGS. 1-3 are cross-sectional diagrams of three operational states
of a portion of a dental appliance, showing a first fluid pressure
actuator embodiment.

[0007] FIGS. 4-6 are various views of another fluid pressure actuator
embodiment.

[0008] FIGS. 7-10 are various views of still another fluid pressure
actuator embodiment.

[0009] FIGS. 1-3 show one embodiment of an actuator assembly and brushhead
assembly in a dental appliance. The actuator assembly 10 and brushhead
assembly 12 are positioned in an appliance housing portion 14. A
plurality of pistons 16-16 are mounted for up/down movement in the
brushhead assembly. Housing 14 and the pistons 16 are typically made from
a plastic material. In one embodiment, there are a total of five separate
pistons, but this number can vary.

[0010] Mounted on the upper surface of each piston 16-16 are a plurality
20 of bristle tufts. Typically, each piston will have a number of bristle
tufts, in the range of five or more. Each bristle tuft will contain
approximately 90 bristles or filaments which can vary in size,
configuration and material. In one embodiment, the bristles/filaments
will have a diameter of 6 mil and will extend approximately 8 mm from the
top of the piston.

[0011] Housing 14 includes two fluid channels 22 and 24. Fluid channels 22
and 24 are defined by housing walls and an interior housing member 34
which extends for the length of the housing. Entrance to fluid channels
22, 24 at the proximal end of the brushhead assembly is through flow
openings 28 and 30. Flow opening 28 is narrow, approximately 1 mm wide in
the embodiment shown. Flow opening 28 extends for the full width of the
housing. Flow opening 30 is larger, approximately 3 mm wide and also
extends for approximately the full width of the brushhead. Flow openings
28 and 30 are defined by flow header elements 32 and 34 which are part of
housing 14. Flow header element 32 extends downwardly from the upper wall
of the housing, while flow header element 34 is positioned at the
proximal end of interior member 34. The size of the flow openings can be
varied to some extent, depending upon the desired action of the
brushhead, although one opening must be quite narrow and the other one
larger.

[0012] Positioned toward the rear of housing 14 in FIG. 1 are a low
frequency spring member actuator 40 and a higher frequency actuator
assembly 42 which in one embodiment is a linear actuator operating on a
piston element which is in fluid-tight contact with the interior surface
of housing 14. A fluid such as water is present in housing 14 forward of
the piston member. Spring member 40 and the higher frequency actuator
assembly 42 operate on the fluid to produce the up-and-down motion of the
brushhead pistons 16 and hence the bristle tufts 20 mounted thereon.
Spring member 40 produces a low frequency fluid pressure action,
preferably within the range of 1-6 Hz, although it could be slightly
higher, while the higher frequency actuator assembly 42 produces a higher
frequency fluid pressure action, within the range of 100-300 Hz. Hence,
there is a combined low frequency/high frequency action on the fluid
within the housing, with the high frequency action superimposed on the
low frequency action.

[0013] FIG. 1 shows the appliance in a null position, i.e. the system is
not operating, wherein all the pistons 16 are in the same neutral
position, with the tips of the bristle tufts being co-planar. FIG. 2
shows the bristle action due to the low frequency action of the spring
member 40, with fluid being forced through narrow opening 28. The low
frequency (1-6 Hz) fluid action results in the bristles
conforming/adjusting to the oral geometry, i.e. the bristle tufts move
with a low frequency in such a manner that the bristle tufts on the
respective individual pistons are moved sequentially against the teeth
for a relatively long period of time. Each of the bristle tufts in turn
contacts and remains in contact with the teeth in accordance with the
frequency of the low frequency actuator.

[0014] The higher frequency fluid pressure action (100-300 Hz) produced by
the linear actuator/piston assembly 42 is superimposed on the low
frequency fluid pressure action provided by the spring member 40. This
higher frequency action produces a frequency of movement of the bristle
tufts between 100-300 Hz. Fluid producing the higher frequency action
moves through the wider flow opening 30, resulting in an effective
tapping action of the bristle tufts, as shown in FIG. 3, by virtue of the
fluid in the higher frequency fluid channel operating on the pistons 16.
The piston action is in the frequency range of 100-300 Hz and produces a
tapping or light hammering action of the bristle tufts against the teeth,
resulting in effective cleaning of the teeth.

[0015] Hence, in this embodiment, the combination of low frequency and
higher frequency fluid action results in an effective cleaning with a
short bristle tuft stroke. The bristle tuft stroke in this case is short
because the higher frequency movement of the bristle tufts begins with
the bristles substantially in contact with the teeth; they first move
away from the teeth during the first half-cycle of the higher frequency
fluid action, and then back to contacting the teeth in the other
half-cycle with a tapping/light hammering action. In the neutral position
the bristles are generally conforming to the teeth instead of being away
from the teeth. This results in a shorter stroke for the bristle tufts,
which is valuable in a limited space, and also permits the bristles to
more readily reach into remote areas of the teeth, i.e. interproximal
areas.

[0016] FIGS. 4-6 show a variation of the above embodiment. It includes a
brushhead housing 34 with an internal fluid channel 35, with fluid such
as water to the right of a piston member 37. A spring actuator 36
provides the low frequency fluid action, while a linear actuator
operating on a piston element 37, such that it moves back and forth in
channel 35 to provide the high frequency fluid action. The brushhead
includes a plurality of piston members 38, on which a plurality of
bristle tufts 38A are mounted. The embodiment includes a first fluid
portion 40 with a narrow entrance 41 and a second fluid portion 43 with a
larger entrance 44. Fluid moves into the first fluid portion 40 through
narrow entrance 41 by action of the low frequency spring member (1-6 Hz),
while fluid moves into the second portion 43 through the larger entrance
44 by action of the higher frequency actuator (100-300 Hz;). The low
frequency action generally conforms the bristle tips to the surfaces of
the teeth, while the higher frequency action produces the higher
frequency tapping action of the bristle tufts against the teeth,
producing the cleaning action. The two fluid actions are thus in effect
superimposed.

[0017] Another embodiment is shown in FIGS. 7-10. In this embodiment, a
dental appliance 50 includes an actuator rod 52 which extends from an
actuator 53. The actuator rod 52 engages a plurality of actuator sections
56-56 (FIGS. 8 and 9). The number of actuator sections for a particular
appliance may vary; however, a typical number will be seven. Usually,
four will be necessary for effective cleaning, although in some
circumstances, a fewer number will be sufficient. Referring to FIGS. 8
and 9, the individual actuator sections are made of a hard plastic, such
as ABS plastic, and are fixedly mounted on an elastic actuator rod 52.
Actuator rod 52 is in the form of a flexible elastic tube or hose, having
a diameter at rest of approximately 2 mm.

[0018] In operation, actuator 53 operates on the elastic actuator rod,
such that it alternately expands from a rest position and then contracts
back to its rest position, at a selected frequency, such as for example
in the range of 100-300 Hz, like the previous embodiment. During
expansion, the diameter of the elastic rod increases approximately 200
microns before returning to a neutral position, although this amount can
vary. This increase and decrease in diameter of the actuator rod forces
an outward opposing expansion of each actuator section 56 about the
actuator rod.

[0019] The expansion action of the actuator sections is due to their
particular configuration, shown most clearly in FIGS. 8 and 9. Each
actuator section is generally in the overall shape of an oval, including
a lower base portion 58 with an upper surface 60. Connecting the opposing
edges 61, 62 of lower base portion 58 is a narrow curved bridge member
63. In the embodiment shown, the actuator sections are each approximately
12.5 mm long, 10 mm high and 3 mm thick (front to back). Bridge member 63
is approximately 0.5 mm wide (top to bottom), except for three hinge
sections 66, 68 and 70 which are located, respectively, at opposing ends
of bridge member 63 (where they meet the lower base portion 58) and at a
mid-point of bridge member 63. Each of the hinge sections is
approximately 0.2 mm wide.

[0020] Extending from upper surface 72 of each bridge member 63 are a
plurality of bristle tufts 74. The bristle tufts can vary in number, but
a typical number will be in the range of 12, while each bristle tuft will
contain approximately 90 individual bristles, for example. The individual
bristles can vary in size and configuration, but are typical bristles for
cleaning teeth, i.e. approximately 8 mm long and 6 mil in diameter.

[0021] The lower section 58, besides having an opening 70 therein for the
actuator rod, includes a slot 76 which extends downwardly from opening 70
to the edge of lower section 58. Positioned above opening 70 is another
opening 78 which comprises two oval-like sections which extend from
opposite sides of the center line of the lower section. A narrow slot 80
connects opening 70 to opening 78. Positioned between opening 78 and the
upper surface 60 of lower section 58 is an additional small circular
opening 82. On opposite sides of opening 82 are two narrow hinge portions
86 and 88, each approximately 1 mm wide (top to bottom).

[0022] In operation, as actuator rod 52 expands and contracts due to the
operation of actuator 53, two mirror-image portions 84, 85 of lower
section 58 move slightly outwardly, away from each other, about hinge
portions 86 and 88. This causes an up/down movement of bridge member 63
because of hinge sections 66, 68 and 70 therein, producing a
corresponding up/down movement of bristle tufts 74 toward and away from
the teeth. This is a tapping/slight hammering action which produces
cleaning of the teeth.

[0023] The above motion of the bridge member 63 relative to the expansion
of the actuator rod is referred to as an amplification factor, i.e. the
relatively small expansion of the actuator rod produces an amplified
(larger) movement of the bristle tufts. An amplification factor (ratio)
of at least seven and up to 40 is possible with the structure shown. As
one example, a 0.25 mm expansion of the actuator rod results in a 1 mm
stroke of the bristle tufts. Thus, an important concept in this
embodiment is that a relatively small expansion of an actuator rod
element can produce an effective bristle tuft stroke length.

[0024] Accordingly, embodiments have been disclosed which provide an
effective bristle tuft action with either a relatively short bristle tuft
stroke and/or a small movement of an actuator element can produce
effective tapping/cleaning action of bristle tufts, directly toward and
away from the teeth.

[0025] Although a preferred embodiment of the invention has been disclosed
for purposes of illustration, it should be understood that various
changes, modifications and substitutions may be incorporated in the
embodiment without departing from the spirit of the invention, which is
defined by the claims which follow.